Incandescent electric lamp



Nov. 29, 1932. J. FORCE 1,889,598

INCANDESCENT ELECTRIC LAMP Filed June 4, I928 Jzxz YENTUE: zTUJV-ATHAN FDA CE;

.HTz-s Arranwzx JONATHAN FORCE, OF CLEVELAND HEIGHTS, OHIO, ASSIGNOR TO GENERAL ELECTRIC Patented Nov. 29, 1932 I COMPANY, A CORPORATION OF NEW YORK INCANDESCENT ELECTRIC LAMP Application filed June 4, 1928. Serial No. 282,591.

My invention relates to electric incandescent lamps having tungsten or other refractory metal filaments. More particularly my invention relates to so-called getters for such lamps. The object of my invention is to provide a getter which will act to reduce blackening of the lamp and also to prevent failure of the lamp on account of the attack of the filament by water vapor.

The early failure of the filaments of incandescent lamps has been due to the so-called Water cycle. Any water vapor which may be in the lamp attacks the incandescent filament forming tungsten oxide which is deposited on the inner bulb surface. At the same time the nascent hydrogen which is liberated attacks this tungsten oxide and reduces it to tungsten which has a black appearance, and the water vapor which is formed by the re-action again attacks the filament. It has been found that the weak points of the filament are those adjacent to the union with the inner leading-in conductors which are clamped to the ends of the filament. According to my invention I dispose adjacent to the filament a powdered refractory metal. such as tungsten or tantalum, and preferably this is placed in contact with the ends of the filament. Apparently this powdered metal it attacked by the water vapor in preference to the. metal of the filament proper and on account of the refractory character of the powder, it does not injure the filament. v.

In the drawing Fig. 1 is an elevation of an electric incandescent lamp to which my invention is applied; and Fig. 2 is a perspective on an enlarged scale of the end of a leading-in conductor and the filament to which it is clamped.

In the drawing the specific lamp shown is of the gas-filled variety and comprises the coiled filament 10, the ends of which are clamped at 1112 to the inner leading-in conductors 1344 which are preferably of ever, ordinary alcohol may be used and the I powder may be painted on or may be applied by dipping. Of course, when the lamp is lit, the binder is dissipated but the powder still seems to hold for a considerable time.

Tungsten or tantalum powder is preferred on account of its refractory character and affinity for oxygcnl In the claims the expression metal of the tungsten class is used to denote metals having high melting points and aifinity for oxygen comparable with tungsten.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric incandescent lamp, the combination of a tungsten filament, leadingin conductors united to the ends of said filament and a quantity of metal of the tungsten class in the powdered state disposed adjacent to the junction of the filament and leading-in conductors.

2. In an electric incandescent lamp, the combination of a tungsten filament, leadingin conductors united to the ends of said filament, and a quantity of tungsten in the powdered state disposed in contact with the junction of the filament and leading-in conductors.

3. In an incandescent electric lamp, the combination of a tungsten filament, leadingin conductors united to the ends of said filament, and a quantity of powder of a metal of the tungsten class surrounding the point of junction of said filament and leading-in conductor. a

4. In an incandescent electric lamp, the combination of a tungsten filament, leadingin conductors united to the ends of said filament and a quantity of a metal of the tungsten class in the powdered state and substantially free from other ingredients surrounding the junction of said filament and leading-in conductors.

In witness whereof, I have hereunto set my hand this 31st day of May, 1928.

JONATHAN FORCE. 

